$output = $pdoFetch->getChunk($tpl, array(
    'files' => $files,
));

if($tpl){
$output = $pdoFetch->getChunk($tpl, array(
    'files' => $files,
));
}
else{
   $output[] = $files;
}

{set $files = '!msGalleryCustom' | snippet}
{foreach $files as $key => $file}
{if $key == 0}
Шаблон для первой картинки
{else}
Шаблон для остальных картинок.
{/if}
{/foreach}

<table class="products">
<thead>
<tr style="font-weight:600;">
	<td>Сплав</td>
	<td>Размер</td>
	<td>Состояние</td>
	<td>Наличие</td>
	<td>Цена</td>
	<td>Примечание</td>
	<td>Фото</td>
</tr>
</thead>
    [[!pdoPage? 
        &element=`msProducts`
        &tpl=`products_row`
        &includeTVs=`prod-img`
    ]] 
</table>

<tr>
	<td class="prod-name">{$pagetitle}</td>
	<td class="prod-size">[[!msOptions? &options=`size` &tpl=`tpl.msOptions-sizes` &product=`[[+id]]`]]</td>
	<td class="prod-sost">[[!msOptions? &options=`sost` &tpl=`tpl.msOptions-sizes` &product=`[[+id]]`]]</td>
	<td class="prod-nalichie">[[!msOptions? &options=`nalichie` &tpl=`tpl.msOptions-sizes` &product=`[[+id]]`]] кг</td>
	<td class="prod-price">{$price | replace:" ":""} руб.</td>
	<td class="prod-primechanie">[[!msOptions? &options=`prim` &tpl=`tpl.msOptions-sizes` &product=`[[+id]]`]]</td>
	<td>[[+prod-img]]</td>
</tr>

$q = $modx->newQuery('modResource');
// условие по необходимости
//$q->where(array('parent' => 1));
$resources = $modx->getIterator('modResource', $q);
foreach($resources as $resource) {
    $content = $resource->get('content');
    // делаем че хотим
    $title = 'Заголовок';
    // ...

    $resource->setTVValue('title', $title);
    $resource->save();
}